Radio direction finding system



Nov. 26, 1940. H. BERTHOLD 2,223,056

RADIO DIRECTION FINDING `SYSTEM Filed July 26, 1938 Hllamey Patented Nov. 26,]1940 A L-; gf

kRADIo yDliuiofrI oN FINDING SYSTEM Applicationsuly ze,issa'seriaiNotzaigzios" M f i ain-Germany Ju1y26,-19371.z-

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tion lfindinglsystems, andmorevsp'ecically tor a I y method of eliminating direction finding errors in such/systems, and'isan improvement uponthe ,fdirectionln'ding radio; system disclosed in'. my 'copendingf United States Patent application'Ser. No. :186,781; filed? 'on v'January- 25,V 1938,'-f-Patent Not/2,188,071, dated Januaryza 194.0.l v z AItisa 'fknowninconvenience .inV connection` with-*radiodirection-nadine ysystems that Idirec:

` tion finding verrors arejintroducedf in leases that a cross-.frame 'aeria1-, f anNS Adcock *or similar 'directive antenna-'system operating with a pluralr'ity' of goniometer devices is utilized for various purposes. Such rdirectie-n finding errors occur as a result of mutual interferences set upbe- 'tween the different members forming part of the system. e, v i l My heretofore mentioned copending United StatesPatentapplication Ser. No. 186,781 relates to an arrangement for eliminating the retroactions above referred to, according to whichy coupling means introduced in the goniometer field coil circuits induce potentials in the goniometer circuits. These potentials in turn'lproduce currentsA of equal amplitude, but oppositely directed with respect to the retroactive currents.'

According to the main feature of my present invention, the coupling means interposed in the goniometer circuitsare sub-divided and arranged symmetrically" with respect to the -goniometer circuits.l A further feature of the invention relates to the structure and method of manufacturing the aforesaid sub-divided coupling means. y

The inventionwill be more readily understoodfrom the following description taken inconjunc- K tion with the accompanying drawings, in which:

, Fig. 1 shows schematically a wiring diagram s. according to one embodiment of the invention,

While Fig. 2 is Vacross section through a cou- The high frequency potentials picked up by the j Referring 'to Fig. 1 whichA substantially cor-` respondsv to the single figure of my aforementioned copending application Ser. No. 186,781,

fstill exists; betweenl the individual 'coils and,

there isshown a cross-frame aerial comprising twoloops I arielk I' intersecting each other at right angles. f These loops, are connected with three 'goniometer circuits I, I'; II, II rand III, III.

, `loops are'impressed upon 'the field coils 5, 6, 'I and 5', Ii', 'I' of the goniometers 8, I9 and I0 through transformers 2, 3, 4 and 2', 3', 4', re-

f spectively. '.Ihey two eld coilsof each goniome- `Hans ljvertholdjerlin, Germanyfassignorvto Y' Lorenz` Aktiengesellschaft, Berlin?'lempelhoLI .Thev present invention' =relates to radioi directerarelar'ranged in perpendicular relation to one i another.v The: findercoils` f'I I,; I2 and vI3 ofthe separate 'goniometers 8,-'9 'and IIIare connected to the apertaining directio'rrf'nding receivers I4, I5 and I6, respectively '"Iv'hediiferencebetweenV the arrangement 'disclosed iny myv cepend-y ingapplication` Ser. No. 186,781 and Vthe present application is `that `'the coupling 'means- I 'Ig I8,1. I9

and II, 5 I8", l' I 9 of said v copen'ding application 'are substituted according tothe main feature of' the present' inventionby sub-'divided coupling which illustrates an arrangement adapted: to

perform the aforementioned compensation with respect to the retroactive currents above referred This compensation device represents the combination of a known inductive coil arrangenecessary windings, and comprises the threeA coils I1, I8 and I9 of Fig. 1. 'I'he compensating` member must satisfy the following requirements, viz. in the first instance that the inductances of the three coils present equal values and, moreover, that the .degree of coupling between these' coils is exactly the same. This is accomplished according to my present invention by applying the coils which are to be coupled with one an' other, that is by way of an example the coils |11, |81 and. |91, on an iron core Vof the aforesaid type. The three wires which areintended to form the three coils are grasped together.v and applied on the iron core in parallel with one another in or-k der to locate the coils in a possibly identical position on the core. This expedient involves the possibility of adjusting the inductance vof the' coils in such manner by varying the position of the iron core that the same degree vof coupling moreover, that each coil presents the same `inductance, since all coils are influenced by theence numeral 4 represents a core composed of a finely dispersed ferromagnetic material and an v:so I

25 ment havinga core of finely vdispersed ferro- *I magnetic iron and a novel application of the insulating material. A spool member 5 which is divided in a plurality of sections, each of which is adapted to receive the same number oi Winding turns is slipped over the core 4. It will be assumed that the coupling coils, e. g. three coils, are to be wound onto the spool member 5, for which purpose the three wires adapted to form the three coils are grasped together and Wound in such manner in parallel relation to one another that the positions of the three nished coils relative to the core are as equal as ever possible.

The corel 4 is supported on a plate or disc 6 likewise oi" nely dispersed ferromagnetic material and the ferromagnetic-coil unit is placed in a casing 1 which may be manufactured of moulding material. 'Ihe inductance value of the device is adjusted by the agency of a -disc 8' of ferromagnetic material fixed in a cover 9 of the casing l. The circumference of this cover and the inner surface of the corresponding end of the casing 'l are threaded inorder to permit the disc 8 to be optionally approached toward or removed from the coil assembly.

What is claimed is: v

1. Direction finding radio apparatus comprising twoy directional antennae, each antenna having a plurality of loop circuits connected thereto, a plurality of radio goniometers each'including a pair of eld coils, one of said coils being connected in a loop circuit of one antenna and the other being connected in a similarly connected loopcircuit of the other antenna, and. each goniometer having a search coil, a pair of coupling means symmetrically connected in each of the loop circuits, the similarly connected ones of each pair in the several loop circuits being mutually coupled with one another so as to produce in said loop circuits currents of substantially equal amplitude but of opposite phase with respect to reactive currents tending toresult from the mutual inuence of said goniometers on each other. v

2. Direction finding apparatus according to claim 1, in which all said coupling means are in the form of windings mounted on a common magneticcore with successive turns of each winding being adjacent the turns of the other Windings so as to produce a maximum of coupling therebetween.

3. Apparatus according to claim 1, in which all said coupling means are in the form of coils mounted on a common magnetic core of iinely dispersed iron, the coils having successive turns interleaved to provide a maximum of mutual coupling.

4. Apparatus according to claim 1, in which all said coupling means are in the form of coils mounted on a common magnetic core oi nely dispersed iron, the coils having successive turns interleaved to provide a maximum of mutual coupling and an adjustable member of nely dispersed iron adjustably mounted with respect to the core for` varying the inductance value and coupling factor of said coils.

y HANS BERTHOLD. 

